Method for utilizing heat of compression

ABSTRACT

Described is a method for utilizing the heat of compression accumulating during a compression process for air-conditioning and/or heating buildings and/or for heating service water. According to the invention, the heat of compression accumulating during the compression process is at least temporarily transferred to at least one consumer that serves for air-conditioning and/or heating a building and/or for heating service water by means of at least one refrigerant circuit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application SerialNo. DE 102009013755.6 filed Mar. 17, 2009.

BACKGROUND OF THE INVENTION

The invention pertains to a method for utilizing the heat of compressionaccumulating during a compression process.

Energy is required for heating and air-conditioning buildings, as wellas for heating service water, and therefore needs to be supplied and/orgenerated directly on-site. In order to lower the energy requirement,excess energy is already utilized for the aforementioned purposes in anumber of applications. In many applications, however, energy is neededfor heating or cooling buildings while energy simultaneously is or mustbe wastefully dissipated because it could not be “recycled” so far.

Natural gas and hydrogen fueling stations feature a number of buildingsthat need to be at least temporarily heated or cooled. If such fuelingstations also feature a car wash, the service water required for thiscar wash also needs to be heated. The natural gas or hydrogen sold atsuch a fueling station needs to be compressed before a vehicle isrefueled. Until now, the heat of compression released during thecompression of these mediums was wastefully dissipated by means of asuitable cooling system—in which water or ambient air is used as coolingmedium. The compression of the aforementioned mediums to pressures up to1000 bar requires an expenditure of energy between 15 and 300 kW,wherein the same amount of energy is generated in the form of heat andhad to be transferred to the surroundings so far with the aid ofcorresponding heat exchangers.

SUMMARY OF THE INVENTION

The present invention is based on the objective of disclosing a methodof the initially cited type for utilizing the heat of compressionaccumulating during a compression process, wherein said methodeliminates the above-described disadvantages and makes it possible, inparticular, to utilize the heat of compression accumulating during acompression process for air-conditioning buildings, for heatingbuildings and/or for heating service water.

In order to attain this objective, the invention proposes a method ofthe initially cited type for utilizing the heat of compressionaccumulating during a compression process, wherein said method ischaracterized in that the heat of compression accumulating during thecompression process is at least temporarily transferred to at least oneconsumer that serves for air-conditioning and/or heating a buildingand/or for heating service water by means of at least one refrigerantcircuit.

Other advantageous variations of the inventive method for utilizing theheat of compression accumulating during a compression process form theobjects of the dependent claims and are characterized in that

-   -   the inventive method is implemented in a gas fueling system, in        which a one-stage or multi-stage compression of a medium,        preferably natural gas or hydrogen, is realized and    -   the medium circulating in the refrigerant circuit consists of        water and/or glycol.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive method for utilizing the heat of compression accumulatingduring the compression process for air-conditioning buildings, forheating buildings and/or for heating service water, as well as othervariations thereof, are described in greater detail below with referenceto the exemplary embodiment illustrated in the FIGURE. However, thisFIGURE merely shows a schematic representation of the inventive method.

DETAILED DESCRIPTION OF THE INVENTION

A gaseous medium to be compressed is fed to a pre-compressor V1 via aline 1 and compressed to a desired intermediate pressure therein. In thecase of a natural gas or hydrogen fueling station, this intermediatepressure lies in the range between 12 and 27 bar. The pre-compressedmedium can either be intermediately stored in a storage device that isnot illustrated in the FIGURE and/or directly fed to the main compressorV2 via a line 1′. The medium is compressed to the desired ultimatepressure in this main compressor. In the compression of natural gas orhydrogen, this ultimate pressure usually lies between 250 and 1000 bar.The compressed medium is subsequently fed to a vehicle to be refueled—ifapplicable after a corresponding intermediate storage—via a line 1″. Thecompression of the gaseous medium to be compressed may also be realizedin only one compression stage or in more than two compression stages.

The pre-compressor V1 and the main compressor V2 are respectivelyprovided with a heat exchanger E1 and E2—that is illustrated in the formof the broken lines connecting the respective compressor and theassigned heat exchanger. The heat exchangers E1/E2 serve for dissipatingthe heat of compression created during the compression in the twocompression stages V1/V2. The temperature usually increases by 50 to 150K per compression stage.

The two heat exchangers E1 and E2 are connected by a refrigerant circuit2-5. A refrigerant that is suitable for the respective applicationcirculates in this refrigerant circuit, wherein the refrigerant mayconsist, in principle, of a one-component or multi-componentrefrigerant. In many applications, it is sufficient and practical to usewater as the refrigerant.

A consumer E3 that receives a medium via a line 6 and discharges amedium heated or cooled therein via a line 6′ is illustrated in theFIGURE in a purely exemplary fashion. The consumer E3 may consist, forexample, of a heater, an air-conditioner or a device for heating servicewater that is preferably realized in the form of an adsorption system,an absorption system or a DEC-system (Desiccant and EvaporativeCooling). In this case, the medium fed to the consumer E3 via the line 6would respectively consist of air or service water. Several consumerswill exist in many applications, but these consumers do not necessarilyhave to always operate simultaneously.

It is advantageous to provide an additional heat exchanger E4 that makesit possible to realize a degradation or dissipation of the energyreleased during the compression—for example in the form of a heattransfer to cooling water or ambient air—when an “energy consumption” bythe or at least one of several consumers E3 is impossible orundesirable.

The inventive method for utilizing the heat of compression accumulatingduring a compression process now makes it possible to cost-efficientlyprovide the energy or the majority of the energy required for heating orair-conditioning buildings.

The inventive method for utilizing the heat of compression accumulatingduring a compression process can also be subsequently implemented inexisting processes or systems, in which a compression process isrealized.

1. A method for utilizing the heat of compression accumulating during acompression process selected from the group consisting ofair-conditioning, heating buildings, and heating service water,characterized in that the heat of compression accumulating during thecompression process is at least temporarily transferred to at least oneconsumer selected from the group consisting of air-conditioning, heatinga building, and heating service water by means of at least onerefrigerant circuit.
 2. The method according to claim 1, wherein themethod is implemented in a gas fueling system, in which a compression ofa medium is realized.
 3. The method according to claim 1, wherein saidcompression of a medium is selected from the group consisting ofone-stage and multi-stage.
 4. The method as claimed in claim 2, whereinsaid medium is selected from the group consisting of natural gas andhydrogen.
 5. The method according to claim 1, characterized in that themedium circulating in the refrigerant circuit is selected from the groupconsisting of water and glycol.